W3C home > Mailing lists > Public > public-apa-admin@w3.org > July 2021

Re: Call for Consensus (CfC): APA Comment on Media Hints

From: John Foliot <john@foliot.ca>
Date: Tue, 13 Jul 2021 09:35:56 -0400
Message-ID: <CAFmg2sUuEnjzWY8ip6A8y0dO2yc6BJST1fwzo=0bLX=-sJ+ACQ@mail.gmail.com>
To: "Janina Sajka (janina@rednote.net)" <janina@rednote.net>
Cc: Accessible Platform Architectures Administration <public-apa-admin@w3.org>
+1

JF

On Tue, Jul 13, 2021 at 9:19 AM Janina Sajka (janina@rednote.net) <
janina@rednote.net> wrote:

> +1
>
> Janina
>
> Janina Sajka writes:
> > Colleagues:
> >
> > This is a Call for Consensus (CfC) to the Accessible Platform
> > Architectures (APA) Working Group testing whether we have group
> > consensus on comments and suggested edits on the MediaStreamTrack
> > Content Hints draft specification, at
> > https://www.w3.org/TR/mst-content-hint/.
> >
> >
> > <beginning of suggested comment>
> >
> > *TITLE *
> >
> > APA comments on the MediaStreamTrack Content Hints draft specification,
> at
> > https://www.w3.org/TR/mst-content-hint/.
> >
> > *OVERVIEW *
> >
> > *Content hint attributes defined in this specification will benefit
> > consumers who rely on assistive technology (AT) and personalization. *The
> > specification notes its focus on end-users' experience: "Adding a media
> > -content hint provides a way for a web application to help track
> consumers
> > make more informed decision[s]...." Content authors can author
> contentHint
> > <
> https://t.sidekickopen90.com/s3t/c/5/f18dQhb0S7kF8cFFTBW4T_qld2zGCwVN8Jbw_8QsRtKVn1vXj1p1kknW16gGBN41Jd6G101?te=W3R5hFj4cm2zwW4mKLS-4mbkbhW49Ldrl308ybGW4fdgvc41YylgW4fdgXQ41YszVW3H90C_3_SMDQW3zh2Fq3K1LvHW49HR8w1Gy-qYW4fGC1K3R0JW00&si=8000000004174048&pi=58151f60-5af3-4f61-ebc9-364d322a7e5a
> >
> >  with the experience of AT users in mind, or UAs acting on behalf of
> > users.  This specification's introduction would be a good place to
> > clarify this as a further benefit of content hints. Content authors may
> > author content hints with AT in mind. In addition, we encourage User
> Agents
> > to make this hint available to downstream consumers via API,
> >
> > *The specification make no mention of hints regarding support files
> *(captions,
> > audio descriptions) that often accompany media content, either linked to
> it
> > in HTML externally (using the <track> element) or furnished 'in-band',
> > e.g., contained within the .MP4 wrapper (HasCaptions: T/F,
> > HasAudioDescription: T/F). If either return True, THEN they need to be
> > exposed in the UI: essentially as 'active' buttons in the Controls. Such
> > support files can be critical to the accessibility of a media track, as
> for
> > example when an American Sign Language video is supplied seperately, but
> > linked. Did the WG consider whether hints could also usefully convey
> > whether the media content has such supporting files?
> >
> > Regarding Section 4: *The specification's hints could address more
> directly
> > some common **audio and video formats that are often encountered with
> > content that has been made accessible. *For clarity, such formats could
> > propose hints such as these (these are examples for clarity only, we
> leave
> > you to define such hints):
> >
> > *For Audio, an additional hint to indicate the presence of
> > audio-description *(or some similar label as you find appropriate).
> > Audio-description is audio that resembles speech-recognition, but does
> not
> > contain data for the purpose of speech recognition by a machine.
> > Audio-description is audio that resembles "speech" but it will likely not
> > be appropriate to apply noise suppression or boost intelligibility of the
> > incoming signal.
> >
> > In the language of the specification (4.1) , "A track with content
> > hint "audio-description"
> > should be treated as if it contains audio data, without background noise,
> > describing in words the activity in the video."
> >
> >
> > *For Video, an additional hint to indicate the presence of transcription
> > embedded in the video*, e.g., motion-with-transcription (or some similar
> > label as you find appropriate). motion-with-transcription would refer to
> a
> > motion video that has, embedded, transcription data, either a
> > picture-in-picture showing a sign language interpreter, or text captions
> > embedded in the video.
> >
> > In the language of the specification (4.2): A content hint of
> > motion-with-transcription should be treated such that one region of the
> > video frame has details that are extra important, and in that region that
> > significant sharp edges and areas of consistent color can occur
> frequently
> > (the area with sign language interpretation, or the area with onscreen
> > captioned text). This screen region would optimize for detail in the
> > resulting individual frames rather than smooth playback. Artefacts from
> > quantization or downscaling should be avoided.
> >
> >
> > *Regarding section 5, the degradation preference does not address
> regions.*
> > Picture regions may be very significant for accessibility. Consider a
> video
> > with sign language interpretation embedded (e.g., in the upper right
> > corner), or a video with captions "burned-in" or embedded (e.g., in the
> > bottom of the picture area). (While APA does not advocate for such
> embedded
> > captions, they are common particularly on social media where the default
> > user behavior is audio "off." These regions would benefit from different
> > encoding decisions than the rest of the frame.  Regions may be encoded
> and
> > decoded quite differently: for example in AVC, "it is also possible to
> > create truly lossless-coded regions within lossy-coded pictures." *We
> would
> > find it useful and supportive of accessible content to make this
> > information available as an RTCDegradationPreference.*
> >
> > Lastly, how are these hints communicated? We note that MP4 files can
> > contain metadata as defined by the format standard, and in addition, can
> > contain Extensible Metadata Platform (XMP) metadata. (source::
> > https://en.wikipedia.org/wiki/MPEG-4_Part_14).
> >
> > *REQUESTS*
> >
> > Correct these two typos:
> >
> >    - Abstract: change "make more informed decision" to either "make a
> more
> >    informed decision" or "make more informed decisions"
> >    - Section 2. change "they appear" to "it appears"
> >
> > Add to the introduction that content hint attributes defined in this
> > specification will benefit consumers who rely on assistive technology
> (AT)
> > and personalization.
> >
> > The WG to ensure that the specification covers use cases with support
> > files, and that hints can be provided for those files.
> >
> > In section 4, ensure that hints support the use-cases mentioned above.
> >
> > In section 5.2 ensure that the specification supports regions
> particularly
> > when such regions are important for accessibility.
> >
> >    <end suggested comment>
> >
> > ***Action to Take***
> >
> > This CfC is now open for objection, comment, as well as statements of
> > support via email. Silence will be interpreted as support, though
> > messages of support are certainly welcome.
> >
> > If you object to this proposed action, or have comments concerning this
> > proposal, please respond by replying on list to this message no later
> > than 23:59 (Midnight) Boston Time, Wednesday 14 July.
> >
> > NOTE: This Call for Consensus is being conducted in accordance with the
> > APA Decision Policy published at:
> >
> > http://www.w3.org/WAI/APA/decision-policy
> >
> > We thank Lionel Wolberger for reviewing this specification on our behalf
> > and for helping lead our teleconference discussions on this
> > specification.
> >
> > Janina and Becky
> >
> > --
> >
> > Janina Sajka
> >
> > Linux Foundation Fellow
> > Executive Chair, Accessibility Workgroup:     http://a11y.org
> >
> > The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
> > Chair, Accessible Platform Architectures      http://www.w3.org/wai/apa
> >
>
> --
>
> Janina Sajka
> https://linkedin.com/in/jsajka
>
> Linux Foundation Fellow
> Executive Chair, Accessibility Workgroup:       http://a11y.org
>
> The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
> Co-Chair, Accessible Platform Architectures     http://www.w3.org/wai/apa
>
>
>

-- 
*John Foliot* | Senior Industry Specialist, Digital Accessibility

"I made this so long because I did not have time to make it shorter." -
Pascal "links go places, buttons do things"
Received on Tuesday, 13 July 2021 13:36:31 UTC

This archive was generated by hypermail 2.4.0 : Thursday, 24 March 2022 20:22:55 UTC